THE MOST EFFICACIOUS COMBINATION OF CHLORTETRACYCLINE,
SULFATHIAZOLE AND PENICILLIN AGAINST ARTIFICIALLY
INDUCED CERVICAL ABSCESSES (JOWL ABSCESSES) IN SWINE1

H. J. Monegue, H. D. Wallace,
and G. E. Combs2

K. L. Bryant

The most frequent cause of cervical abscesses in swine is group E streptococci.
The significance of jowl.abscesses is that they are one of the leading causes of
carcass condemnation and thus an economic problem. The loss due to abscesses is
estimated to be increasing by $400,000 annually. Therefore the control of group
E streptococci is of major concern3.

The objective of this study was to determine ,1h most efficacious combination
of chlortetracycline, sulfathiazole and penicillin against artificially induced
cervical abscesses (jowl abscesses) in swine. 6

Experimental .X

Ninety weanling pigs with an initial weight of approximately 50 pounds were
divided into 15 pens of 6 pigs each according tosex, weight and litter. The
animals were self fed in a facility with partially slotted floors and automatic
watering devices.

This public document was promulgated at an annual cost of
$102.00 or .10 cents per copy to inform county agricul-
tural directors, ranchers and growers of research results
in swine management and nutrition.

After 7 days on the prescribed diets, artificial inoculation with a culture
of Streptococcus lymphadentitis Group E, Serotype IV into the nasal cavity of
all pigs was accomplished by Dr. LeRoy Olson of the University of Missouri
(Veterinary Pathology Dept.). The inoculum was prepared from stock cultures
supplied to Dr. Olson by Dr. C. H. Armstrong of Purdue University. A loop of
stock culture was incubated in trypticase soya broth at 370 C for twenty-four
(24) hours and then plate counted. The pigs were inoculated with ml per nasal
cavity using a tuberculin syringe with a blunt gauge needle. Caution was taken
to inject the inoculum during the inspiration phase of the breathing cycle.

All pigs were individually weighed at time of allotment, just prior to
inoculation and after 3, 6, 9, 12 and 15 weeks following inoculation. Feed con-
sumption was determined for all experimental intervals and feed conversion data
were calculated for each pen of pigs for each interval.

Rectal temperatures were obtained on all pigs on 2 days pre-inoculation,
just prior to inoculation, and 2, 4, 6 and 8 days post-inoculation.

At the end of 15 weeks post-inoculation all drugs were removed from the
rations. Seven days later all pigs were slaughtered at the University of Florida
Meats Laboratory and carefully examined by a Federal slaughter inspector and Dr.
Davis Thanjan of Diamond Shamrock Chemical Company for jowl abscesses. Each

Pig performance Six and fifteen week daily gain and feed conversion data
are summarized in table 2. During the first six weeks of the trial control pigs
(0-0-0) gained slower than all treated groups. This reduced performance was also
quite evident at the end of the first three weeks of the trial, suggesting that
the challenge organism created an adverse effect at the time or shortly after
challenge. The temperature data support this conclusion. The two treatments
which included the lower levels of penicillin (100-100-25) and (100-100-50)
promoted faster rates of gain than other drug treatments. The average efficiency
of feed conversion through the first six weeks was very similar for all drug
supplemented groups and slightly less efficient for control pigs. By the end of
fifteen weeks a somewhat similar pattern of performance remained evident. The
drug supplemented lots showed about the same rates of gain and similar feed
efficiencies. Control pigs had gained about 5% slower and required about 5%
more feed per pound gain.

Body temperatures Rectal temperatures are summarized in Figure 1. In
general the temperatures 2 days pre-challenge were higher for all pigs than would
be considered normal. There is no ready explanation for this other than the
excitement resulting from the first exposure to temperature recordings. In most
cases temperatures were more nearly normal at the second measurement (day of
challenge). On day 2 post-challenge there was a significant rise in rectal tempera-
tures for pigs fed the control diet (0-0-0). The mean temperature increase in pigs
in these pens approached 20 F and the pigs were feeling ill as indicated by list-
lessness and poor appetites. This condition prevailed for 2-3 days post-challenge.
By the 4th day post-challenge temperatures had returned to normal and remained so
as indicated by subsequent measurements. All drug combinations fed effectively
prevented the post-challenge temperature elevations, listlessness and poor appe-
tites observed in the control pigs. Penicillin did not seem to be a critical
antibiotic in this regard. When measured at 96 hrs. post-challenge temperatures
of all pigs in all pens were normal.

Cervical abscesses After nine weeks on the experiment a careful check of
each pig revealed six externally visible abscesses. All abscesses, with one
exception were observed in control pigs. During the period from 9-15 weeks there
appeared to be some regression in the abscesses. Certainly there was no continued
growth. At slaughter, a careful examination of all pigs, revealed three large
abscesses in control pigs and one small abscess in a pig from group "B". Some of
the abscesses observed at 9 weeks had entirely regressed.

- 4 -

Summary

Ninety young pigs weighing an average of 50 pounds initially were used to
determine the most efficacious combination of chlortetracycline, sulfathiazole
and penicillin against artificially induced cervical abscesses in swine. After
seven days on the prescribed drug combinations all pigs were challenged with
Streptococcus lymphadentitis Group E, Serotype IV and continued on test for 15
additional weeks. Post-challenge body temperatures remained normal for all
groups fed the various drug combinations while all control groups showed elevated
temperatures on day 2 post-challange. These control groups were also marked by
listlessness and poor appetites for a short period of time. Penicillin, regard-
less of supplementary level, was not essential for the prevention of temperature
elevations. After 6 weeks, gain and feed conversion data indicated that all
drug combinations had improved rate of gain and efficiency of gain. Penicillin,
at the lower levels of 25 and 50 gm/ton in combination with chlortetracycline
and sulfathiazole (each 100 gm/ton) promoted the most efficient overall perfor-
mance. The addition of 100 gm penicillin tended to depress performance to the
approximate level attained with the combination of chlortetracycline and sulfa-
thiazole with no penicillin. Visual observations revealed several growths
(abscesses) at the end of 6 weeks. Five of these abscesses were seen in pigs
in the control lots and one was observed in a pig fed the diet containing
100-100-50 gm/ton of chlortetracycline, sulfathiazole and penicillin respectively.
Except for the initial performance setback observed in control groups, all pigs
performed reasonably well throughout the remainder of the test. After 15 weeks
control pigs had narrowed the margin for rate of gain and feed conversion but
the same general trends as observed after 6 weeks were apparent. Examination of
all pigs at slaughter revealed only four cervical abscesses. Three were found
in control pigs and one was found in a pig fed the diet containing 100 gm chlor-
tetracycline, 100 gm sulfathiazole and no penicillin. All pigs were marketable
and no carcasses were condemned at slaughter.